An exit poll is taken of 3000 voters in a statewide election. Let X denotes the number who voted in favor of a special proposition designed to lower property taxes and raises the sales tax. Suppose that in the population, exactly 50% voted for it.
a. Explain why this scenario would seem to satisfy the three conditions needed to use the binomial distribution. Identify n and p for the binomial.
b. Find the mean and standard deviation of the probability distribution of X.
c. Using the normal distribution approximation, give an interval in which you would expect X almost certainly to fall, if truly p = 0.50.
d. Now, suppose that the exit poll had x = 1706. What would this suggest to you about the actual value of p ?

  • CreatedSeptember 11, 2015
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